Rider and drum for lithographic presses



RIDER AND DRUM FOR LITHOGRAPHIC PRESSES .Filed Dec. 31, 1926 FEM,-

6 presses using the soft rubber lating and otherwise),

ink

a great -ograph1c offset Patented June 25, 1929.

TES PATENT OFFlCE.

THOMAS C. GOW ANS OF BROOKLYN, NEW YORK.

B1DER AND DRUM FOR LITHOGRAIHIC PBESSES.

Application filed December 31, 1926. Serial No. 158,302.

This invention relates to lithographic offset presses and in particular to the riders and oscillating drums used therein.

Since the advent of lithographic ofiset rollers, technically known as form rollers, arisen whereby the riders and drums (oscilbecome stripped of their ink, it of course being understood that 1c. the function of these riders and drums is to carry the ink to the form rollers, which engage the form which does the lithographing. In the use of these lithographing plates, water is a necessary the plate and form rollers; As the art of lithography is based on the resistance of this film to take ink while damp, it will be readily 2o seen that a difiicult proposltion confronts the operator of the press in order to make the riders and drums retain their ink. The film of water is purposely created on the lithographic metal plates, so that it will resist the but this water gets to the form rollers and consequently to the riders and drums with the result that they will not transfer the ink rosion of the drums and riders made of metal 3 so that water thereon will not effect the rough surface thereofto resist the spreading of ink over the riders and drums during the latters oscillation, it being of course understood that the oscillation and revolving movement of the 35 drums spread the ink evenly over theintermediate roll from which it is transferred to the riders and hence from the form rollers to that portion of the lithographic plate meant to receive it, but this corrosion by artificial 40 means, soon becomes sufiiciently smooth so that the water effects the same and the result is that it will not take the ink. This is-called stripping and of course necessitates stopping the press during'the work, which is not only loss of time but additional expense in removing the drums for reconditioning so that they will take ink.

A particular object of my invention, therefore, is to provide a drum or rider for a lithpress, which will overcome this condition and which need not be reconditioned at anytime in order that it will properli transfer the ink. 5

.' further object of my invention is to provide a particular type of drum or rider around element and during its use, a 15 grease-resisting film is formed on the riders and drums by the action of the water from a condition has er1 properly. An expedient isthe original corthrough against their adjacent rollers.

which can be moulded a sleeve, which, whcr worn can be removed from the form or core and another sleeve moulded thereon which can be made up at small cost and used over a long period of time in a press withoutrecov- Austill further object of the invention is to provide a cover of hard rubber or vulcanite which can be moulded on to the core of the riders and drums and which will be so arranged as to withstand the side thrust and rotary friction of the drums and riders To enable others skilled in the art to fully comprehend the underlying features of my invention that they may embody the same in the various modifications in structure and relation contemplated, a drawing depicting a prefzerred form has been annexed as a part of this disclosure and in such drawing, similar reference characters denote correspondin parts throughout all the views, of which,

*igure 1 is a fragmentary view in sectional elevation showing the arrangement of the oscillating drum and rider and the intermediate rollers as used in the ordinary form of lithographic offset press..

Figure 2 is an enlarged, top plan view of an.

oscillating drum, a portion thereof being shown in section, the same being covered with my improved coating or sleeve of hard rubber or vulcanite.

Figure 3 is a sectional view taken on the line.3 3 of Figure 2, the same being shown broken for compactness of illustration and showing in cross section the arrangement of the parts necessary in the the oscillating drums, and I Figure 4 is a sectional view taken on the line 4-4 of Figure 3 showing the method of driving said oscillating drum.

Referring to the drawings in detail, 5 indicates a press frame of any particular type, having pivoted therein the ink roller 6 which operates in the cut-out bottom of an ink reservoir 7, the ink being transferred from said ink roller 6 to the adjacent oscillating drum 8 e medium of a movable roller 9. which moves back jand forth fromv contact with roller 6 to contact with, drum 8. The drum 8, of course, is separated from the rider 10 throng the medium of an intermediate roller 11 d the rider 10 is separated from the cylinder bg a form roller 12; These rollers 11 and 12 are-made of soft rubber so that they manipulation of will carry the ink intermediate stiff rollers or oscillating drums and riders, as they may be termed, and are termed in the art, it is necessary that theybe coated with a rigid material so that they can be moved longitudinall the ink on the form r0 lers.

In experimenting with different substances with which to coat or make the drums or riders, I found that only metal will take the ink resistin film while hard rubber or vulcanite, celluloi j or bakelite and even enamel and paint offers resistance to this ink resisting film. I did find, however, that hard rubber and-vulcanite have the greatest resistance and have therefore adopted the hard rubber as the covering forthe oscillating drums and riders which are disposed adjacent the form rollers.

' When the leather covered form rollers were .20 in use, the transfer of,thisink resisting film was not so pronounced but since the composition and rubber form rollers are in general use, that is the soft rubber rollers, the condi- "tion is very noticeable.

v As embodied in the press, the oscillating drums are carried on a spindle 13 which is held at its end in the frame 5 of the press and on this spindle 13, is mountedthe oscillating sleeve 14 which carries at one- 'end, a driven gea 15 which is constantly in mesh with an elo ated driving gear 16, thedriving gear 16 being positioned upon a ack shaft 17 held in frame pieces and operated through the medium of the driving sprocket 18, the opposite end of the sleeve 14; carries a slotted collar 19, which isengaged by the oscillating arm 20, it being. evident that the ossillating of the arm 20causes movement of the sleeve 14 longitudinally of the spindle 13, 4 while the same is being driven through the medium of the driving gear 16. The sleeve carries at its intermedlateportion,the drum or rider core '21 which may be made of metal, wood, or other rigid material, the face thereof being grooved'as at 22-so that the/hard rubber sleeve 23, when moulded thereon will engage in said slot-0r groove 22;and prevent longitudinal movement of saidsleve 23 relatively to the cores 21 when they sleeve 14' is given an oscillatory movement lengthwise of the shaft or, spindle 13. This oscillatory movement is imparted to the that the ink will be'evenly distributed on the but in order to provide the to evenly distribute 'oscillating-druml or rider whic be subjected to as they :ent practice.

invention with some drum-or rider so form rollers and the revolving motion of the drum or rider is taken care of through the iiieedium of the gear 15 and its driving mem- It is to be distinctly understood that the groove 22 in the core 21 may be circumferential'and spaced one from another depending upon .th diameter of the core or the groove 22 may e one continuous spiral cut in the periphery of the core 21and may be of any depth desired, into which the sleeve 23 may be cast so that the same will be held securely on said core 21 It is evident, therefore, that I have. rovided an improved oscillating drum and rlder construction to be used 'in'lithographic offset presses which will resist ,the ink resisting film and will at all timeisvcarry a surface which will efficiently hold ink transferred thereto by the adjacent rollers.- i. V

It is evident, also thatI have rovided an does not 7 have to lie-continually reconditioned so that it will carry the ink on its surface and also one which will have a'minimum of wear and which can be made up at a relatively smaller cost than the reconditioning process to which so the drums or riders would otherwise have to must be in the pres While I have illustrated and described my degree of particularity, I realize that in practice various alterations therein maybe made. I therefore reserve the right and privilege of changin the form of the details of construction or otherwise altering the arrangement of .the correlated parts without departing from, the spirit of the invention or the scope of the appended claim,

Having thus described my invention what I claim as new and desire to secure by United States Letters Patent is An ink transfer drum arranged for revolving and oscillatory-movement comprising a spindle, a sleeve on the spindle movable longitudinally thereof, a core on said sleeve made of rigid material and having a spiral groove 100 of substantially rectangular cross section cut in the face thereof-and a sleeve of hard rubberfmoulded on the periphery of the core and in the groove. Y In testimony whereof I aflix m THOMAS C. GOWAN signature. 

